Traditionally, bindings for touring skis, Telemark skis or cross-country skis require release manipulation in order to open the binding or preparation manipulation to enable the boot to be fitted. Apart from the opening of the binding, it is practically always necessary to effect manual action directly by hand or by means of a ski pole for locking the boot on the ski.
In Telemark, the most usual equipment is bindings in accordance with the “75 mm standard”, such as for example the bindings described in the U.S. Pat. No. 7,401,802 (Black Diamond Equipment). This type of binding is characterized by a fixed front clamp that holds the so-called “ducks beak” shape situated at the front of the boot and a cable tension system equipped with a spring locking on the heel of the boot. This boot standard makes it tricky to walk on rocks when climbing, does not allow the use of standard glacier crampons and limits the use of this type of boot solely to the Telemark ski. In addition, fitting the boots in the bindings is always very tricky. The skier is often obliged to place a knee on the ground in order to lock the ski and to be able to lock the tension system on the heel of the boot. These operations are made more difficult when snow is present, since the skis, being rarely equipped with a ski stop, easily slip, sometimes making the locking operation tedious. Finally, ejection of the ski in the event of a fall is practically impossible, and the use of these bindings therefore has a high risk of injury for skiers.
In the middle of the years 2000, a group of manufacturers defined a new standard, referred to as “New Telemark Norm” or NTN, which established a novel ski/boot interface standard. The novel boots defined by the standard can be used with a Telemark or alpine ski, and can receive normal glacier crampons. The sole of the boot is divided into two parts: the front sole, specific to the NTN standard, and the heel, which is conventional and separate from the front sole. The specificity of the front sole stems from the projection that is situated at the arch at the middle of the boot, at the rear end of the front sole. Thus the boot can be secured to the ski while being held between the front part of the front sole and the projection. This standard made it possible to create bindings that combine the freedom of movement of the heel particular to the Telemark and include a safety device releasing the ski in the event of the skier falling. Responding to several problems with the 75 mm standard, these bindings can also include ski stops and afford additional safety for skiers.
The Telemark bindings as described in the document EP 1 790 396 (Rottefella) are binding models complying with the NTN standard. These bindings do however require manual release, tricky fitting of the boot and action for locking the latter by hand, with the free hand or using a ski pole. These bindings are also characterized by a weight greater than the average of the bindings available on the market.
In parallel to the development of these bindings, boot manufacturers have included, in certain models in their range, front and rear interfaces particular to bindings of the Dynafit® type. These interfaces of the Dynafit® type are characterized by the presence of two hollow conical inserts situated on the front tip of the sole and an insert plate on the heel. NTN Telemark boots equipped with these interfaces enable the skier to use them either on skies equipped with an NTN Telemark binding or on skis equipped with tourist bindings to the Dynafit® standard. Users greatly appreciate the versatility of this type of new generation of boot. The invention described in the present patent application uses this model of boot.
Starting on the basis of this concept of boot to the NTN standard and equipped with a Dynafit® interface, a binding model has appeared, associating the front part of the Dynafit® binding and the locking tension system on the heel of the boot particular to Telemark fixings to the “75 mm standard”. This system ensures the holding of the front of the boot by means of the clamps (forks) of the Dynafit® binding, while the tensioning of the boot is provided by the conventional heel block system held by the cable/spring assembly of the Telemark bindings to the “75 mm standard”. This system makes it possible to obtain a functional and effective assembly in Telemark mode, with a reasonable weight and effective in tourist skiing, but does however require manual locking of the boot and limits the safety of the skier because of difficulty in ejecting the skis.
Finally, through U.S. Patent Publication No. 2003/0047912, a ski binding is known, the “step in” function of which is provided by two levers, one of which is articulated on the base of the binding and the other one of which can slide, by means of its free end, in a slot in this base. The boot locking zone is moreover secured to the sliding lever with respect to translation. When the user presses downwards on the locking zone, the latter drives the lever sliding forwards, so that this locking zone tends to advance with respect to the boot, which performs the fixing operation proper.
The problem addressed by the present invention is to allow both automatic locking of the boot in the binding, the use of the binding in tourist mode without detachment of the skis, easy ski detachment actuated by the skier and automatic ski detachment in the case of a fall, while using a binding with a total weight that is as low as possible.